DESC:FIELD
The present disclosure relates to a device that separates and removes any liquid that is carried along with a gas.
DEFINITIONS
Liquid: The term ‘liquid’ used hereinafter refers to a liquid such as water in predominantly liquid state but may include small quantities of gas, oil or solid particles.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
In process control systems, pressurized gas is generally used for actuation of the valves. The gas pressure is modulated in a device called a ‘positioner’. The control valve positioner takes feedback form the process and adjusts the gas pressure to the actuator. Any positioner, mechanical or electronically controlled, comprises miniaturized mechanisms which are critical in operation. Positioner mechanisms have small orifices and delicate diaphragms.
The gas entering into the control valve positioners, if not clean and dry, can badly hamper the operation of the control valve positioner. Ultimately, it affects the quality of response from the system.
Ideally, an automatic liquid removing device should be located after the gas pressure regulator of the control valve positioner so as to ensure 100% removal of water from the gas. High quality strainers are required to be used to ensure dirt does not enter the control valve positioner.
In general, in any process plant, liquid draining systems are located at the outlet of a gas compressor that supplies pressurized gas to the valve system through the control valve positioner. Such systems are manually operated and need to be operated intermittently. Such systems are not foolproof and are not adequate for maintaining the quality of gas that is required for the desired operation of the control valve positioner.
Thus, there is felt a need for a liquid removing device for a control valve positioner which alleviates the aforementioned drawbacks of prior art.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide an automatic liquid removing device for a control valve positioner that requires dry and clean gas for actuating valves.
Another object of the present disclosure is to provide an automatic liquid removing device for a control valve positioner, which has a foolproof mechanism.
Yet another object of the present disclosure is to provide an automatic liquid removing device for a control valve positioner, which does not require manual intervention.
Still another object of the present disclosure is to provide an automatic liquid removing device for a control valve positioner, which is efficient and facilitates continuous removal of liquid to supply dry gas to the control valve positioner.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages a liquid removing device for a control valve positioner. The control valve positioner is configured to allow pressurized gas to pass therethrough. The liquid removing device is configured to be in fluid communication with an inlet manifold of the control valve positioner to separate and remove any liquid that is carried along with the gas that enters the control valve positioner. The liquid removing device comprises a flow deflector configured to separate liquid droplets from the gas. The device further comprises a base having an orifice configured thereon. A valve seat is mounted on the orifice. The valve seat has an opening that allows flow of liquid through the orifice and through the device. A mounting bracket is fitted to the base. A lever is pivotably attached to the mounting bracket at an operative first end of the lever. A valve head is formed on the lever. The valve head is configured to close the opening of the valve seat when the lever is in a lowered state. A float is pivotably attached to the lever at an operative second end of the lever. The lever is configured to rotate about the mounting bracket due to the buoyant force of the float exerted by the liquid rising in the enclosure of the device to lift the valve head from the valve seat.
In an embodiment, the device includes a main pivot pin for attaching an operative first end of the lever to the mounting bracket.
In another embodiment, the device includes a float pivot pin for attaching the float to an operative second end of the lever.
In yet another embodiment, the float is a sphere or cylinder having a circumferential extension configured to receive the float pivot pin.
In one embodiment, the valve seat is integrally mounted on the base.
In another embodiment, the valve seat is removably mounted on the base.
In an embodiment, the center of gravity of the float, in a lowered state of the lever, is configured to be positioned closer to the axis of the valve head than the second end of the lever.
In another embodiment, the axis of the valve head lies between the first end and the second end of the lever.
In yet another embodiment, the axis of the valve head lies proximal to the operative first end of the lever.
In one embodiment, the buoyant force of the lever is ,
where,
Fb: Buoyant force required to operate the float mechanism;
Fp: Pressure force acting across the orifice by the virtue of differential pressure;
Fw: Force due to self-weight of the float; and
x, y, z: Moment Lever arms for the forces for Fp, Fw, Fb respectively.
In another embodiment, a predetermined clearance is provided between the farther surface of the float and a proximal wall defining an enclosure boundary of the enclosure of the device in a raised state of the lever.
In yet another embodiment, the device includes a manual over-ride configured to prevent jamming or operation failure of the mechanism.
In yet another embodiment, the device has a transparent body.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
A liquid removing device, of the present disclosure, for a control valve positioner will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a liquid removing device along with a positioner of the present disclosure;
Figure 2 is a sectional view of an automatic liquid removing device mechanism of the present disclosure;
Figure 3 illustrates a free-body diagram of the automatic liquid removing device mechanism of Figure 2;
Figure 4 illustrates an enclosure of the liquid removing device in a closed state; and
Figure 5 illustrates an enclosure with the liquid removing device in an open state.
LIST OF REFERENCE NUMERALS
10 liquid removing device
01 float
02 lever
03 main pivot pin
04 mounting bracket
05 valve seat
06 float pivot pin
07 base
08 valve head
11 orifice
12 manual over-ride
15 liquid outlet of liquid removing device
20 positioner
25 dry gas inlet to positioner
26 wet gas inlet
30 enclosure
H1 initial level of CG of float
H2 final level of CG of float
DETAILED DESCRIPTION
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Description of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practised and to further enable those of skill in the art to practise the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiment herein.
The description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
The present disclosure envisages a liquid removing device 10 for a control valve positioner 20. The control valve positioner 20 is configured to allow pressurized gas to pass therethrough. Figure 1 shows a positioner 20 provided with a liquid removing device 10 (hereinafter referred to as ‘the device 10’). The liquid removing device 10 is designed to separate and remove any liquid that is carried along with the gas that enters the control valve positioner 20 through the gas inlet 25. It also stops dirt or foreign particles entering into the control valve positioner 20. The liquid is removed from the liquid removing device 10 through the liquid outlet 15. The liquid removing device 10 is configured to be in fluid communication with an inlet of the control valve positioner 20.
Figure 2 shows the liquid removing device 10 which comprises a flow deflector configured to separate liquid droplets from the gas. The device 10 further comprises a base 07 having an orifice configured thereon. A valve seat 05 is mounted on the orifice. The valve seat 05 has an opening that allows flow of liquid through the orifice and through the device 10. A mounting bracket 04 is fitted to the base 07. A lever 02 is pivotably attached to the mounting bracket 04 at an operative first end of the lever 02. A valve head 08 is formed on the lever 02. The valve head 08 is configured to close the opening of the valve seat 05 when the lever 02 is in a lowered state. A float 01 is pivotably attached to the lever 02 at an operative second end of the lever 02. The lever 02 is configured to rotate about the mounting bracket 04 due to the buoyant force of the float 01 exerted by the liquid rising in the enclosure 30 of the device 10 to lift the valve head 08 from the valve seat 05.
More specifically, in an inoperative condition, the valve head 08 is seated on the seat 05. As and when the lever 02 is actuated in an operative condition of the device 10, by virtue of the buoyant force of the float 01, the lever 02 rotates about the main pivot 04, thus resulting in opening of the seat 05. The float 01 and the lever 02 are designed such that the buoyant force generated is sufficient enough to open the valve head 08 against the moments due to self-weight of the mechanism and the force due to differential pressure across the orifice 09. Opening of the orifice 09 leads to discharge of the accumulated liquid along with any dust, dirt through the outlet 15.
Figure 3 illustrates a free-body diagram showing the forces acting on the lever 02 of the liquid removing device 10.
The moment balance equation for the lever 02 is:

where,
Fb: Buoyant force required to operate the float 01;
Fp: Pressure force acting across the orifice by the virtue of differential pressure;
Fw: Force due to self-weight of the float 01; and
x, y, z: Lever arms for the forces in the order Fp, Fw, Fb respectively.
For a given set of (a) differential pressure, (b) size of the orifice 09 and (c) self-weight of the float 01, the required buoyant force Fb depends on the distance of the forces from the main pivot 03. If the distances x and y increase, the required buoyant force increases. To optimize the forces in the mechanism, the distances x and y should be as minimum as possible.
The distance ‘x’ has a constructional constraint as ‘x’ is the distance of the orifice 09 from the main pivot 03. The distance ‘y’ is the distance of resultant center of gravity of the float 01 and the lever 02 from the main pivot 03. As the weight of the float 01 acts along the center of gravity, whose location remains close to the geometric center of the float 01, the distance ‘y’ is reduced.
In the automatic mechanism of the liquid removing device 10, the float 01 is pivotably mounted on the lever 02. Thus, the buoyant force acts at the main pivot 03, resulting in increase in lever arm ‘z’ for buoyant force. Secondly, by virtue of the pivot joint, the center of gravity of the mechanism lies quite close to the main pivot 03, reducing lever arm ‘y’ for force due to weight.
Therefore, an optimum buoyant force is required to operate the automatic mechanism of the liquid removing device 10 of the present disclosure.
The liquid removing device 10 of the present disclosure has been designed such that there is not pressure drop in the pressure of the gas flowing downstream therefrom. The liquid removing device 10 continuously discharges liquid as and when the liquid enters the device 10. There is no sudden opening and closing of the device orifice, which helps in reducing the pressure variation/ pressure drop in the gas flow.
In an embodiment, the device 10 includes a main pivot pin 03 for attaching an operative first end of the lever to the mounting bracket 04. In another embodiment, the device 10 includes a float pivot pin 06 for attaching the float 01 to an operative second end of the lever 02. In yet another embodiment, the float 01 is a sphere or cylinder having a circumferential extension configured to receive the float pivot pin 06.
In one embodiment, the valve seat 05 is integrally mounted on the base 07. In another embodiment, the valve seat 05 is removably mounted on the base 07.
In an embodiment, the center of gravity of the float 01, in a lowered state of the lever 02, is configured to be positioned closer to the axis of the valve head 08 than the second end of the lever 02.
In another embodiment, the axis of the valve head 08 lies between the first end and the second end of the lever 02. In yet another embodiment, the axis of the valve head 08 lies proximal to the operative first end of the lever 02.
In another embodiment, a predetermined clearance is provided between the farther surface of the float 01 and a proximal wall defining an enclosure boundary of the enclosure of the device 10 in a raised state of the lever 02.
Moreover, the liquid removing device 10 is compact and therefore, can be installed and or integrated with any positioner without any constraint. The device 10 is compact and casting-friendly by the virtue of the flexibility due to the pivoted float 01. The device 10 optionally has a built-in strainer (not shown) that restricts the entry of dirt into the control valve positioner 20. Overall, the liquid removing device 10 enhances the performance and life of the control valve positioner 20.
In an embodiment, the device 10 includes a manual over-ride 12 configured to prevent jamming or operation failure of the mechanism.
In another embodiment, the device 10 has a transparent body for providing visual indication of the operation of the device 10.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a liquid removing device, which:
• does not need any manual intervention for removing liquid from gas automatically;
• helps in reducing the pressure variation/ pressure drop in the gas flow;
• is compact and casting-friendly by the virtue of the flexibility due to pivoted float;
• is compact and therefore, can be installed and / or integrated with any positioner without any constraint; and
• enhances the performance and life of the control valve positioner.
The foregoing disclosure has been described with reference to the accompanying embodiments which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, or group of elements, but not the exclusion of any other element, or group of elements.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.
,CLAIMS:WE CLAIM:
1. A liquid removing device (10) for a control valve positioner (20) configured to allow pressurized gas to pass therethrough, said liquid removing device (10) configured to be in fluid communication with an inlet manifold of said control valve positioner (20) to separate and remove any liquid that is carried along with the gas that enters the control valve positioner (20), said liquid removing device (10) comprising:
• a flow deflector (not shown) configured to separate liquid droplets from the gas;
• a base (07) having an orifice (11) configured thereon;
• a valve seat (05) mounted on said orifice (11), said valve seat (05) having an opening that allows flow of liquid through said orifice (11) and through said device (10);
• a mounting bracket (04) fitted to said base (07);
• a lever (02) pivotably attached to said mounting bracket (04) at an operative first end of said lever (02);
• a valve head (08) formed on said lever (02), said valve head (08) configured to close the opening of said valve seat (05) when said lever (02) is in a lowered state; and
• a float (01) pivotably attached to said lever (02) at an operative second end of said lever (02), said lever (02) configured to pivot about said mounting bracket (04) due to the buoyant force of said float (01) exerted by the liquid rising in the enclosure (30) of the device (10) to lift said valve head (08) from said valve seat (05).
2. The device (10) as claimed in claim 1, which includes a main pivot pin (03) for attaching an operative first end of said lever (02) to said mounting bracket (04).
3. The device (10) as claimed in claim 1, which includes a float pivot pin (06) for attaching said float (01) to an operative second end of said lever (02).
4. The device (10) as claimed in claim 3, wherein said float (01) is a sphere or cylinder having a circumferential extension configured to receive said float pivot pin (06).
5. The device (10) as claimed in claim 1, wherein said valve seat (05) is integrally mounted on said base (07).
6. The device (10) as claimed in claim 1, wherein said valve seat (05) is removably mounted on said base (07).
7. The device (10) as claimed in claim 1, wherein the center of gravity of said float (01), in a lowered state of said lever (02), is configured to be positioned closer to the axis of said valve head (08) than the second end of said lever (02).
8. The device (10) as claimed in claim 1, wherein the axis of said valve head (08) lies between the first end and the second end of said lever (02).
9. The device (10) as claimed in claim 8, wherein the axis of said valve head (08) lies proximal to the operative first end of said lever (02).
10. The device as claimed in claim 1, wherein the buoyant force of said lever (02) is ,
where,
Fb: Buoyant force required to operate said float (01);
Fp: Pressure force acting across the orifice by the virtue of differential pressure;
Fw: Force due to self-weight of the float (01); and
x, y, z: Moment Lever arms for the forces for Fp, Fw, Fb respectively.
11. The device (10) as claimed in claim 1, wherein a predetermined clearance is provided between the farther surface of said float (01) and a proximal wall defining an enclosure boundary of the enclosure (30) of said device (10) in a raised state of said lever (02).
12. The device (10) as claimed in claim 1, which includes a manual over-ride (12) configured to prevent jamming or operation failure of the device (10).
13. The device (10) as claimed in claim 1, which has a transparent body.